Even if Senators are able to agree to a debt ceiling and government spending framework on Tuesday, any one senator could delay the chamber from passing it until Friday — a day after the Treasury says it will run out of money to pay the nation's bills.

On Monday, Sen. Joe Manchin III, D-W.Va. indicated that Democrats have not gotten assurances that all GOP senators will give up their rights to filibuster and allow the Senate to expedite its proceedings. If Sens. Ted Cruz, R-Texas, Mike Lee, R-Utah, or another potential opponent of the emerging deal objected, 60 senators would be needed to break a procedural filibuster on the motion to open debate.

"I think it just depends on what the leaders come up with and how they want to position it," Manchin said.

Still, Manchin expressed optimism the tight timeline would not be a barrier to preventing a government default. "We will not default. I'm positive of that. I feel very positive of that," Manchin said. "Nothing is a sure thing, but let's just say I'm as sure as I can be on that one. With that being said, just the timing of our procedural votes would take us up to that [deadline]."

Lee demurred when asked whether he was prepared to use procedural tools to push any vote to the last minute.

"I don't ever answer questions like that in the abstract. Procedural judgment calls have to be made in the moment, in context," Lee said on whether he would block a time agreement to move more quickly.

Senate Majority Leader Harry Reid, D-Nev., has a number of options he could pursue, but Democrats don't appear to have devised a procedural path just yet.

One option that Reid may consider could be a tool created earlier this year under the Senate's filibuster rules deal. Under those new rules, Reid could expedite a bill's consideration if he allows up to four amendments. Of course, those amendments could complicate the Senate's ability to prevent "poison pills" from being adopted and potentially further delay passage.

If Reid doesn't use that option, he might have to try to break a filibuster on the motion to proceed. In any event, he needed to file a motion to invoke cloture, or limit debate, on Monday night in order to hit a Thursday target for possible final passage. Thursday is the day Treasury says it will run out of extraordinary measures to prevent a default.

But Reid adjourned the Senate on Monday evening without setting any procedural wheels in motion. That decision was likely a nod to the fact that any deal will need sign-off from a significant number of both Republicans and Democrats. Both caucuses are expected to discuss the proposed framework Tuesday.

Many senators had not returned to Washington on Monday, despite scheduled votes on judicial nominees.

If Reid decides to file cloture on Tuesday and any senator objects to a shortened time agreement, a vote on final passage could be pushed to Friday.